Knife blade



w. GRANT- 1mm:` BLADE Filed Fon. 6.,..1950

fama/wwf@ patented Feb. 17, i931 UNITED sArEs PATENT ori-'ICE l GRANT, FSHEFFIMJD, ENGLAND i KNEE BLADE Application led February 8, 1980, SerialNo. 426,409, and in Great britain February 16, 1929..

This invention relates to lrnie blades of termined by the general shapeof the blade. the type in which aseries of grooves is ground A series ofgrooves in the form of rounded in one or both of the blade surfacesadjacent depressions 8 is then ground in one or both to the cuttingedge, the object of the invenof the blade'surfaces to meet the edge 7withtion being to provide an improved formation out intersecting it. Asshown in the drawin le of cutting edge which is particularly applieachof the groove depressions 8 is of a roun cable for use 1n cuttingtomatoes, fruit and ed Outline extending from the cutting edge 7 thelike, although the invention may be yapand the surface enclosed by theoutline is also plied with advantage in other circumstances. of arounded sha e. The groove de ressions Knife blades are known withclosely ar- 8 are preferably ibrmed by means ofp a grindso rangedgrooves of a narrow V-section proing disc or wheel having a roundedoperative ducing a series of points on the blade edge edge. Althoughvarious sizes of grinding and it has been proposed to make the groovesdiscsl may be used the preferred size has a I of a rounded outline andof a semi-circular diameter of about three or four inches and a isection in one or both surfaces of the blade, thickness of about half aninch to three-q'uaro5 but such rounded grooves have been sepaters of aninch, its edge being approximately rated by substantial lengths of theori 1inal semi-circular in transverse section. edge and all the knownforms of grooves ave In order that the groove depressions 8 may beenmade to become gradually deeper tomeet the edge 7 without intersectingit they mi wards the cutting edge to intersect that edge are each madeto become radually shallow- To and thus to form notches therein.YAccording er towardsthe edge 7 as s own in Figure 3. to the presentinvention, however, the grooves The central portion of the base of thisshalt l are in the form of rounded depressions havlowing part of thedepression is thus at a ing rounded outlines disposed in close proxmoreacute angle with the 'opposite surface irnity to one another and meetingthe cutting of the blade than the one in which it is 75 edge of theblade without intersecting it so ground, andiis preferably substantiallyparalthat the edge retains its original shape. This lel to the oppositesurface adjacent to the may be eilected by making each of the groove ede as shown in Figure 3. depressions to become gradually shallower tispreferred to rovide the groove dew towards the cutting edge, preferablyso that pressions 8 alternate y Ain both surfaces of so a part of thebase of the depression is subthe blade as illustrated, those in onesurface stantially parallel to the opposite surface of being situatedbetween those in the other surthe blade adjacent to the edge., face. Ifdesired, however, they may all be lnthe accompanying drawing z-n formedin one surface. Figure l is an elevation of a lrniie accordl As thegroove depressions 8 are made to se in to the present invention. meetthe cutting edge 7 without intersecting igure 2 is an elevation on anenlarged it as illustrated, this edge will retain its shape,

scale of part of a blade illustrating a slight but where each groovedepression meets it, p niodicatiom preferably as a chord of asemi-circle as ill Fi ure 3 is a transverse section, exaggeratlustrated,there will be a region of thinner ce ing t e thickness for the sake ofclearness, metal adjacent to the cutting edge producon the line 3-3 ofFigure 2, and ing a razordilre ed e, whilst between the Figure t is afra entary view looking at groove depressions t e normal blade structheedge of the bladgurexn ture will provide the necessary strength and MLike reference numerals indicate like parts support. The groovedepressions are diso5 throughout the drawing., posed in close proximityto one another in i In carrying out the present invention a one or bothsurfaces and may be practically miie blade 6 is irst ground to a normalcutcontiguous as illustrated in'Figure l, or they tin edge 7 having nosubstantial thickness may be separated by relatively short unan of theusual straight line or curve degrooved portions 9 of the blade asillustrated 100 2 y ifeaivi in Figure 2 to increase the portion ofnormal blade structure strengthening and supporting the razor edgeproduced by the formation of the groove depressions 8.

To obtain the best results from the present invention the size of thegroove depressions 8 is an important factor. if they are too small thereisa danger o producing a jagged saw-like edge, Whilst if they are toothere Will be insuicient support given to the central portions of therazor-like cutting edge produced by the groove depressions. In thepreferred forni and size the Width of the depression is a maximm at thecutting edge and this width is approximately a quarter of an inch, sothat when the groove depressions are formed imboth surfaces of the bladethe centre of one is se arated from the centre of the next one in t esame surface by approximately half an inch. This distance will, however,be slightly increased when adjacent groove depressions are sep arated byshort ungrooved portions 9. The dimensions given may, however, beconsiderably varied without departing from the invention.

What l claim is l. A knife blade having a series of depres sions in itssurface adjacent to the cutting edge and meeting that edge Withoutintersecting it, substantially as specified.

2. A knife blade having a series of rounded depressions having roundedoutlines in its surface dis osed in close proximity to one another anmeeting the cutting edge of the blade Without intersecting it,substantially as specified.

3. A knife blade having a series of round ed depressions having roundedoutlines al ternately disposed in the two surfaces of the blade in closeprorimity to one another and meeting the cutting edge of the bladeWithout intersecting it, substantially as specified.

4;. A knife blade having a series of depressions in its surface formedto become gradually shallovver towards the cutting edge and to meet thatedge Without intersecting it, substantially as specified.

5. A knife blade having a series of depressions in its surface/meetingthe cutting edge without intersecting it and having the central portionof the base of each de ression at a more acute angle with the oppositesurface of the blade than the one in which it is formed, substantiallyas speciied.

6. A knife blade having a series of depressions in its surface formed tobecome radually shallovver towards the cutting edge to meet that edgeWithout intersecting it and with the base of such shallowing partsubstantially parallel to the opposite surtace of the blade adjacent tothe edge, substantially as specified.

' 7. A knife blade having a series of rounded depressions having roundedoutlines signature.

WlLLlAh/ GRAN El

